120 bpm is generally considered normal - but one of my best dance
experiences ever, with the band "Old Grey Goose" left me both feeling
sublime, and realizing their tempos were on average a little lower than i
was used to. Ralph Sweet has a great thought about tempo - the idea that,
based on the length of the average human leg, there is a frequency of
motion at which the least force is expended to set it swinging (imagining
the dancer's leg as a pendulum)...
And i suppose that, like everything about dance music and calling, what is
ideal really depends upon the dancers present. Suffice it to say i've had
great experiences as a dancer around 118, but when i'm really "into" a tune
on the fiddle, it's easy to warp up to 126 without realizing it. As a
fiddler new to playing for dancers, if your technique on notey reels is up
to snuff, it's easy to get carried away and confuse "energy" with speed -
sometimes the hardest thing is slowing down. On the dance floor that
confusion never happens, fast is just fast... and less enjoyable to dance.
Hence my making a somewhat conservative suggestion.
tavi